Philadelphia, PA (CBS) — Floyd Mayweather feels confident, as he should, for his May 3rd challenge from Marcos Maidana at the MGM Grand in Las Vegas. But there’s someone that always seems to haunt the undisputed best pound-for-pound fighter in the world and that’s the constant specter of Manny Pacquiao.

As Mayweather (45-0, 26 knockouts) prepares to defend his WBC/WBA welterweight titles against Maidana, he couldn’t help but take a few more verbal jabs recently at Pacquiao, who was coming off his revenge rematch with Tim Bradley a few weeks ago.

“Bradley went out there and fought his heart out, but I think he was throwing a lot of shots like an amateur; I think both fighters fought like amateurs,” Mayweather said. “Pacquiao fought like an amateur. I wasn’t pleased with his performance. He got the victory, but I saw something totally different from Pacquiao. I don’t see the same power in Pacquiao’s shots; I don’t see the same snap in his shots. He’s getting tired. I didn’t see him getting tired before. I’m seeing something totally different. I’m still sharp. I’m still smart. I don’t get fatigued. I don’t know if you guys see it, but that’s what I see.”

What fight fans could see is another virtuoso performance by “Money May” against the hard-punching Maidana (35-3, 31 KOs), who earned the shot at Mayweather by beating Mayweather wannabe Adrien Broner in December.

Mayweather said he may stay in front of Maidana and make him miss. His best, Mayweather promises, is still yet to surface.

“In 18 years I haven’t brought my best out yet. Being around the sport for so long, I have a lot of experience. I’ve boxed my whole life. I’ve never worked a job,” Mayweather said. “I’m pretty sure [Maidana] is going to be well-rounded and ready for this fight. I’m going to take my time and if the guys leaves an opening and pick the guy apart. I am the bigger guy. I’m the naturally bigger and have been at 147 for almost 10 years now.”

Maidana does carry heavy hands, but it’s a matter of hitting Mayweather, the most difficult thing to do in all of sports. Zab Judah once said Mayweather’s defense is so airtight and his reflexes so prescient that he could see the punches develop before they’re thrown.

He’s had a history of reducing quality fighters into mere shadows of themselves.

“I can feel a guy when he’s going to throw a punch,” Mayweather said. “Whatever a guy’s biggest attribute is, whatever he does best, my goal is to take it away from him and force him to do something else. Maidana punches extremely hard, by his knockout ratio, but when a guy is throwing a lot of big shots, they get fatigued like that.”